We study the thermodynamics and the chemical potential for a five-dimensional charged AdS black hole by treating the cosmological constant as the number of colors N in the boundary gauge theory and its conjugate quantity as the associated chemical potential µ. It is found that there exists a small-large black hole phase transition. The critical phenomena are investigated in the N 2 -µ chart. In particular, in the reduced parameter space, all the thermodynamic quantities can be rescaled with the black hole charge such that these reduced quantities are charge-independent.Then we obtain the coexistence curve and the phase diagram. The latent heat is also numerically calculated. Moreover, the heat capacity and the thermodynamic scalar are studied. The result indicates that the information of the first-order black hole phase transition is encoded in the heat capacity and scalar. However, the phase transition point cannot be directly calculated with them.Nevertheless, the critical point linked to a second-order phase transition can be determined by either the heat capacity or the scalar. In addition, we calculate the critical exponents of the heat capacity and the scalar for the saturated small and large black holes near the critical point.
Reconstructing the Cenozoic environmental history of Hetao Basin, in the northern part of the Ordos Plateau in North China, is important not only for revealing the evolution of the Yellow River, but also for understanding the formation of the Hobq Desert. Here we present the stratigraphic framework of drill core DR01 with length of 2503.18 m, and the results of magnetostratigraphic and ESR dating and multi-proxy analyses of drill core WEDP05 with length of 274.60 m, from the Hetao Basin. The magnetostratigraphic and ESR results indicate that core WEDP05 spans the last ~1.68 Ma. Stratigraphic sequence of core DR01 indicates that the Hetao area was uplifted and eroded during the early Cenozoic, before subsiding to form a sedimentary basin. Subsequently, the basin was a fluvio-lacustrine environment during the Pliocene and then experienced alternating desert and fluvio-lacustrine conditions during the Quaternary. Sedimentary facies and multi environmental-proxy analyses of core WEDP05 indicate that the basin was occupied by a fluvio-lacustrine system during the following intervals: ~1.47-~1.30 Ma, ~1.17-~1.07 Ma, ~0.68-~0.60 Ma and from ~0.47 Ma to the last interglacial; and that a desert environment developed during the lake regression phases of ~1.30-~1.17 Ma, ~1.07-~0.68 Ma and ~0.60-~0.47 Ma. The presence of aeolian sand at the base of core WEDP05 suggests that the origin of the Hobq Desert can be traced back to the early Pleistocene, and resulted from the erosion and transportation of exposed fluvio-lacustrine sediments by near-surface winds associated with the Asian winter monsoon. A large river channel in the Hetao Basin may have existed as early as the Pliocene, which was 3 occupied by the Yellow River when its upper reaches formed by at least ~1.6 Ma. Subsequently, at least since ~1.2 Ma, the Yellow River formed its drainage system around the Hetao Basin and controlled the paleoenvironment evolution of the basin.
In northwestern China, carbonate δ 18 O variation has been closely associated with evaporation and precipitation, whereas the variation of carbonate δ 13 C generally reflects patterns of palaeovegetation. Located within the transitional zone between the Chinese Loess Plateau and the Tibetan Plateau, the Lanzhou Basin has developed a continuous sequence of Cenozoic sediments which have been subjected to detailed sedimentological and high-resolution magnetostratigraphic analyses. In the present study, pedogenic carbonate O and C isotopic analyses were obtained throughout the entire Cenozoic sequence. The δ 18 O record exhibits a general positive trend with several abrupt changes. A dramatic positive shift in the δ 18 O record at ~33 Ma indicates the initiation of the aridification process within the basin, which was likely associated with the late Eocene westward retreat of the Tethys Sea and global cooling. Two significant positive shifts in the δ 18 O record at ~22 Ma and ~3.5 Ma are synchronous with major increases in aeolian dust deposition on the Chinese Loess Plateau and in the North Pacific Ocean, suggesting the intensified aridity of the Asian interior, which is likely related to the stepwise uplift of the Tibetan Plateau via the blocking of water vapour pathways. The δ 13 C values exhibit a weak positive trend with a remarkable shift at ~3.5 Ma. This trend is likely related to a decrease in vegetation density in response to the ongoing Cenozoic aridification, whereas the shift at ~3.5 Ma may reflect the large-scale expansion of C 4 plants.
By neglecting the effects of self-force and radiation, we investigate the possibility of destroying the Kerr-MOG black hole through the point particle absorption process. Using the instability of event horizon and equation of particle motion, we get the upper and lower energy bounds allowed for a matter particle to produce the naked singularity. We find that the energy gap always exists between the upper and lower energy bounds for both extremal and near-extremal black holes, which means some tailored particles can actually lead to the violation of the weak cosmic censorship conjecture. However, when considering the effect of the adiabatic process, the result shows that the Kerr-MOG black hole gets more stable instead of a naked singularity, and thus the weak cosmic censorship conjecture can be restored at some level.
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